title: Development and preliminary validation of the PC-SAD5, a screener-derived short depression severity measure.
abstract: BACKGROUND
  The prevalence of depressive disorders is high among patients with skin disease. The PC-SAD is a 37-item self-administered depression screening questionnaire that has been validated in dermatological patients.
  
  
  OBJECTIVE
  The aim of this study was to develop and validate a brief depression severity instrument derived from the PC-SAD that can be used to assess severity and monitor ongoing clinical course.
  
  
  METHODS
  Two patient samples participated in the study: 72 adult dermatological inpatients and 73 adults attending six primary care practices. Psychiatric assessment included the Structured Clinical Interview for DSM-IV and an 18-item version of the PC-SAD; moreover, dermatological patients completed the Patient Health Questionnaire depression scale (PHQ-9), while primary care patients were administered the Montgomery-Asberg Depression Rating Scale (MADRS). A subset of five PC-SAD items showing the best psychometric properties were selected, and the reliability and validity of the resulting instrument (PC-SAD5) were examined.
  
  
  RESULTS
  The PC-SAD5 showed satisfactory internal consistency in both samples. There was a high correlation between PC-SAD5 and PHQ-9 and MADRS scores. Multiple regression analysis revealed a gradient of PC-SAD5 scores from patients with no mental disorder, those with milder forms of depression, to those with Major Depressive Disorder. Similar results were observed for the 18-item version of the PC-SAD.
  
  
  CONCLUSIONS
  The availability of valid and reliable continuous measures of depression severity derived from the PC-SAD extends its field of application from depression screening to use as a follow-up measure of depression severity in routine clinical practice. A validated very short instrument such as the PC-SAD5 may have substantial clinical value.
authors.affiliation: Mental Health Unit, Centre of Epidemiology, Surveillance and Health Promotion, Italian National Institute of Health, Rome, Italy. angelo.picardi@iss.it
authors.forename: A
authors.initials: A
authors.lastname: Picardi
authors.forename: D A
authors.initials: DA
authors.lastname: Adler
authors.forename: H
authors.initials: H
authors.lastname: Chang
authors.forename: I
authors.initials: I
authors.lastname: Lega
authors.forename: A
authors.initials: A
authors.lastname: Gigantesco
authors.forename: P
authors.initials: P
authors.lastname: Pasquini
authors.forename: G
authors.initials: G
authors.lastname: Matteucci
authors.forename: M P
authors.initials: MP
authors.lastname: Zerella
authors.forename: M
authors.initials: M
authors.lastname: Caredda
authors.forename: L
authors.initials: L
authors.lastname: Tarsitani
authors.forename: M
authors.initials: M
authors.lastname: Biondi
authors.forename: W H
authors.initials: WH
authors.lastname: Rogers
mesh_terms: D000328:Adult; D003863:Depression / Q000175:diagnosis* / Q000523:psychology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D012720:Severity of Illness Index; D012871:Skin Diseases / Q000523:psychology*; D011795:Surveys and Questionnaires